Welcome Back "Famman"
I am not all that familar with Lake Springfield. Have only fished it once (Youth Bass Tournament). Really like it.
There is a regular report posted on 'Larry's Fishing Hole'
http://members.aol.com/ladoz2/spots.html
Currently stating "WhiteBass are FAIR-GOOD early on twister tails at Lindsey Bridge and around beach area. "
Know on Shelbyville catch a lot on jigging spoons.
Watch where the gulls are getting after the shad. You'll find white bass close by if not just under the shad.
Hope this will help. Maybe some others taht fish Springfield will jump in and give you better help.
Barry